Rectifying means



Dec. 26, 1933. c. SPAETH ET AL RECTIFYING MEANS Filed May 4, 1927 //YPOTi C [527'5672 Peary fig? Patented Dec. 26, 1933 UNITED STATES- PATENTOFFICE Application May 4, 1927 Serial No. 1882130 3 Claims;

Qur invention relates to rectifying means and morepanticularly toa pointto plate rectifier and has for its object the provision of airectifierof this character which will be easily assembled and when assembled willbe strong and rugged so as in the rectifier tube and properly spacingthem.

Other objects and advantages of the invention will appear as thedescription proceeds when taken in connection with the accompanyingdrawing. However, we wish it to be distinctly understood-that We donotintend tojlimit ourselves to, the exact details shown and described, butthat we intend to avail ourselves to-all such modifications as occur toone skilled in this art and as fall within the .scope of the claims.

In the drawing: v p I The figure is. a sectional view of a full waverectifier embodying the invention. n V 1 Referring now in detail to thedrawing, the numeral 5 indicates the usual evacuated tube housing therectifier. This tube is preferably evacuated to a veryhigh state ofrarefaction and is then filled with a suitable gas such as one of thenoble gases such as helium or neon. .The

tube is provided with the usual base 6 and in the form shown in thefigure has four terminals '7, 8, 9, and 10 for connection to theexternal clearly have an annular outwardly extending circuits in amanner which will be presently explained. The tube is provided with theinwardly projecting stem or press 11 and extending upwardly from thispress with the lower ends embedded therein are the metallic rods 12 and13 forming the point electrodes for the full wave the cathode and hasthe other end supported rectifier.

Surrounding the electrodes 12 and 13 and resting upon the upwardlyextending portions 14 and 15 of the press 11 are the insulatingsupporting members 16 and 17 which are provided adjacent the topsthereof with the annular shoulders '18' and 19 forming a seat for thecathode 20 which is substantially cup-like in shape. This electrode isprovided in the bottom thereof with a plurality of enlarged openingsreceiving the inverted cup-like members 21 and 22 which as shown 3; eachprovided at thetopthereof as at 23 and .24 with an opening considerablylarger in diameter than the rods 12 and 13 and through which the saidrods project. and .22 are firmly-held in place by upwardly projectingportions of the. insulating members 16 and 17 above the shoulders 18 and19 which have a tight fitwithin the members 21 and 22. To fully enclosethe point electrodes within the cathode we provide in addition the cap25 which is secured upon the-cupdike member 20 by means of the flangesat 26 and 2'7 provided on both the members .20: and .25 and thesupporting rods28 and 29 which extend through these flanges and are bentover so as to retain the flanges together, the lower ends of the rods 28and 29 being molded .in the press 11'.

In accordance with the'well-known operation The members 21 of point toplate rectifiers, the plate or cathode 20 oper'atesat atemperature belowthat at which the discharge is dependent upon-thermionic emission. Theliberation of electrons from the cathode surtace. occurs, according tothe accepted theory of operation of such devices, mainly as a result ofthe bombardment of that surface by ,periment that the introduction of aheated filament in proximity to the point to plate rectifier greatlyincreases the current rectifying capacity of the rectifying tube and theform of the 'invention illustrated is provided with such a filament 30which as shown has one end secured to by means of the insulating bushing32 in electrode31 and has a conductor 33 extending therefrom downwardlythrough the press 11 to the terminal 7. It will be noted, howeven'thatthe addition of the filament has not changed the fundamental operationof my device. tion in the arrangement as shown in the drawing is stilldependent on the difierence in size between the restricted pointelectrodes 12 and 13 and the plate or cathode 20. These point electrodes12 and 13 are connected by means of the conductors 34 and 35 to theterminals 8 and 10 and the cathode is connected by means of theconductor 36 to the terminal 9.

.In the operation of the tube a transformer having the primary 38 andsecondary 39 is connected across the usual 110 volt supply ofalternating current. In order to supply the filament with current theterminals 7 and 9 which are connected respectively to the filament andthe cathode are also connected across the source of alternating current.The opposite ends of the secondary of the transformer are connected tothe terminals 8 and 10 and the transformer is preferably such that arelatively high voltage in the neighborhood of 300 volts will beimpressed upon the point electrodes 12 and 13. The secondary transformeris tapped midway between its ends andprovided with the lead 40 formingone terminal of theoutput circuit while the terminal 9 is connected by.

means of the lead 41 to the other side of the output circuit so thatupon connecting the primary of the transformer to a source ofalternating current, direct current will be supplied continuously to theoutput circuit by means of the leads 40 and 41 substantially in themanner described in the application of Charles Spaeth on rectifier filedMarch 4, 1927, under Serial No. 172,701.

The particular advantages obtained by the improved mounting of theelectrodes are first, increased strength and rigidity, since thecup-like members 21 and 22 together with the shoulders and upwardlyextending reduced portions on the insulating bushings serve to firmlyretain the electrodes in properly spaced relation, and-second protectionof the plate and point electrodes at their areas of support by thebushings. In a rectifier of this character the heaviest currentdischarge takes place across the shortest gap between the electrodes. Bythe use of the cup-like members 21 and 22 this discharge is made to takeplace at the free ends of these members so that it occurs at a distancefrom the support and the supporting portions are not worn away so as toimpair the device structurally by the heavy discharge of current. 5

From the above description itis thought that the construction andoperation of the device will be clear to those skilled in this art andhaving thus described our invention what we claim and desire to secureby Letters Patent of the United States is: a

1. A rectifier comprising a gas filled envelope having a supporting stemtherein, spaced metallic rods projecting from said stern insulatingbushings surrounding said rods, and having annular shoulders thereonadjacent their upper ends, inverted cup-like metallic members havingannular flanges resting on said shoulders and projecting above the upperends of said bushings, said inverted members having openingstherethrough through which said rods extend, and a cup-shaped metallicmember having spaced openings in the bottom thereof receiving saidinverted members, whereby said cup-shaped member engages and issupported by said flanges.

2. A rectifier comprising a gas filled envelope having a supporting stemtherein, spaced metallic rods projecting from said stem, insulatingbushings surrounding said rods and having annular shoulders thereonadjacent their upper ends, inverted cup-like metallic members havingannular'fianges resting on said shoulders and projecting above the upperends of said bushings, said inverted members having openingstherethrough through which said rods extend, and a cup-shaped metallicmember having spaced openings in the bottom thereof receiving saidinverted members, whereby said cup-shaped member engages and issupported by said flanges, and a cap for said cupshaped member formingtherewith a complete housing for the free ends of said rods, a filamentin said housing, said housing supporting said filament therein spacedfrom said rods.

3. A rectifier comprising a gas filled envelope having a supporting stemtherein, spaced metallic rods projecting from said stem, insulatingbushings surrounding said rods, and having tubular projections at theirupper ends closely surrounding said rods, metallic shields surroundingand projecting above the upper ends of said tubular projections, saidshields having annular flanges resting upon said bushings, and a cupshaped metallic member having spaced openings in the bottom thereofreceiving said shields, whereby said cup shaped member engages and issup ported by said flanges.

" CHARLES SPAETH. HERBERT PEARY.

